Tension control means in rotary presses for printing and blanking



April 10, 1956 R. F. HOLLIS TENSION CONTROL MEANS IN ROTARY PRESSES FORPRINTING AND BLANKING Filed June 15, 1951 2 Sheets-Sheet l P Q Q Q (D 0Q) Q) r I x I A j I/ (D O I/ [NI 5N 7 02. Zane-Pr F 1 /0445,

Apnl 10, 1956 R. F. HOLLIS 2,741,176

TENSION CONTROL MEANS IN ROTARY PRESSES FOR PRINTING AND BLANKING FiledJune 13, 1951 2 Sheets-Sheet 2 FIGZ, z 59 F103.

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United States Patent TENSION CONTROL MEANS 1N ROTARY PRESSES FORPRINTING AND BLANKING Robert F. Hollis, Alton, Ill.,assignor to Alter:Box Board Company, Alton, 112., a corporation of Delaware ApplicationJune 13, 1951, Serial N 231,407

6 Claims. (Cl. 101-227) This invention relates to apparatus forcontinuously printing and blanking paper board boxes and in particularto such apparatus having multi-color rotary printing presses and rotaryblankers.

Eflicient continuous multi-roll rotary printing and blanking of paperboard of the character of soap box fiber has heretofore been extremelydifiicult and, in fact, has not been achieved. The board is ofsubstantial thickness and high tensile strength. Obtaining properregistry of the printing rolls is particularly troublesome since the twosides of the board may present difierent frictional characteristics, andtension sufiicient to produce a substantial slippage of the boardthrough the printing rolls can be built up before the web breaks.Furthermore, the creaser, slitter and die rolls, which comprise theblanker section of box-printing presses exert an influence on theprinting section which is not met in presses in which light-weight paperis run to produce stamps, newspapers, and the like.

The paper board box printing and blanking machines known heretofore havegenerally contained many of the elements of the machine of the presentinvention, including a feed roll, a printing section comprising a numberof separate printing presses each printing a different color, a pullroll following the printing section and a blanker section following thepull roll. In certain of the prior art machines the registry of thepresses has been governed, though somewhat unsuccessfully heretofore, byelectronic means wherein electric eyes responding to marks printed atintervals along the web by the first printing cylinder operate to speedup or slow down the subsequent printing cylinders. A narrow range ofadjustment of the speed of the feed roll with respect to the rest of thesystem was also included in certain of the prior art machines.

However, the object of the designers of the prior art machines was tomake the machines as inflexible as possible, to which end the efiforthas been directly to gear together all of the elements of the machine.In certain of the prior art machines the various elements are crowdedtogether as closely as possible in an attempt to eliminate ditficultiesarising from sections of board with different surface characteristicsbeing in the machine at the same time. In other machines of the priorart the web is extended between the several printing rolls and betweenthe printing section and the blanker section in an attempt to use theresilience of the web to comp ensate for. variations in tension betweenthe various elements. In any event, in the paper board box printingrotary presses and blankers known heretofore there has been such a greatdeal of trouble with breakage of the web, with slippage between theprinting rolls and the web, with improper blanking and with looping orblistering of the .web, as tomake the machines almosi impractical.

One of the objects of this invention is to provide a paper hoard Totarypress and blanker having a highestpacity with high efiiciency. Otherobjects will become apparent to those skilled in the art in the light ofthe following specifications and accompanying drawings.

In accordance with this invention, generally stated, a rotary press forprinting and blanking paper board hoxes having a feed roll, a printingsection, a blanker section, and a pull roll beyond the printing sectionbut ahead of the blanker section, is provided with a tensioning devicebetween the printing section and the pull roll for introducing a knownand substantially uniform tension in the web. The tension device is soconstructed as to move when the tension of the web tends to change, andis equipped to indicate the tendency of the tension of the web tochange, either visually or otherwise, so that the tension balance in theweb can be restored. The pull roll and a blanker pull roll are soconstructed and controlled as to be instrumental in regulating thetension of the web and in damping the pulse of the web set up by thedriven rolls of the blanker section.

In the drawing:

Figure l is a diagrammatic view in two parts of a device constructed inaccordance with this invention;

Figure 2 is a detail view in side elevation of an intermediate pullroll;

Figure 3 is a sectional view taken along the line 33 of Figure 2;

Figure 4 is a plan view of one embodiment of tensioning means; and

Figure 5 is a view in side elevation of the tensioning device shown inFigure 4.

Referring now to the drawings for an illustrative embodiment of thisinvention, and in particular to Figure l, a stand 1 carries a roll 2 ofpaper board being fed to the'press. A driven pull roll 3 pulls the boardfrom the roll 2. V The paperboard web 4 from roll 2 passes over thetower roll 5 and through driven roll 6 to produce a loop 7 in the web 4.The tower mechanism is provided in connection with a splicer, not hereshown, and forms no part of the present invention. From the loop 7 inwhich there is, of necessity, no tension, the web passes between the nipand driven rolls of the main feed roll 8. From the main feed roll 8 theweb passes into a printing section 100, in which there are, in theembodiment shown, four intaglio presses. The web passes over idler roll9, and then between impression roller 10 and an intaglio printingcylinder 11 which comprise first printer 12. The web then passessuccessively through second printer 13, third printer 14, and fourthprinter 15. In the diagrammatic view shown, the arrangement of rolls andcylinders in each of the subsequent printers is identical with those offirst printer 12 and they are so numbered. From the final printer 15 theweb passes under an idler 16 and through a tension device 17. In Figurel the tension device 1-7 is shown diagrammatically as consisting of anupper idle roll 20 and a lower idle roll 21, mounted on a swinging frame22. The swinging frame 22 is pivoted at a point equi-distant from theaxes of rotation of rolls 20 and 21.

Connected to the swinging frame 22 in such a way as to bias the upperroll 20 in a direction away from the printingsection is a weigl1t25.Also attached to swinging frame 22 is an indicator 28 of a gauge 29.From the tensioning device 17 the web passes over an idler 30, betweenan air-loaded bottom nip roll 31 and an intermediate pull roll 32, andbetween intermediate pull roll 32 and an air-loaded upper nip roll 33.The term air-loaded is used to describe an arrangement whereby a roll isbiased by means of compressed air as contrasted for example with aspring. biased or loaded roll. From upper nip roll 3 3 the web passesover a. series of. idler rolls 34 to. the blanker section 49. At thehead of the '3 7 a blanker section 49 is a polished, chromiumplatedblanker pull roll 41 followed by creaser rolls 42, slitter rolls 43, dierolls 44, waste cut-off rolls 45, turning roll 46, and carton conveyor47 upon which the printed, knockeddown boxes emerge for stacking.

Power for the entire machine is supplied by a large motor 50 through amain line shaft, divided into two sections 51 and 52. In the embodimentshown, pull roll 3, roll 6, feed roll 8, and the driven rolls of theprinting section 101) are driven by the main line shaft 51. All of theblanker rolls except the blanker pull roil 41 are geared directly tosecond section 2, and pull roll 32 and blanker pull roll 41 are drivenby that section. The sections 51 and 52 of the main line shaft aredivided by a variable speed transmission 55 and a differential gear 56to which is attached an air motor 57. Between the section 52 of themainline shaft and the intermediate pull roll 32 is a variable speedtransmission 60. Between the section 52 of the main line shaft and theblanker pull roll 41 is 'a variable speed transmission 61. Between thefeed roll 8 and the section 51 of the main line shaft is a variablespeed transmission 62. Variable speed transmissions 55, 60, 61, and 62may be of any suitable sort. The so called P. I. V. of the Link BeltCompany, a number of suitable models of which are described matically inFigure l, the swinging frame 22 is made up of side channels'lSfi topchannel 151 and bottom channel 152. .Upper roll and lower roll 21 aremounted to rotate freely on shafts 155 which extend between sidechannels 150. The swinging frame 22 is itself mounted for rotation on apair of stub shafts 156 carried by pillow blocks 157 mounted on theframe of the machine. A cable quadrant 160 is mounted in the center ofthe top 'channel 151 at right angles to the axis of the swinging frame22. A cable 161 passes over the cable quadrant 169 through sheave 162and over a sheave 163 to support the weight 25. The weight is made up of'a number of removable disks 165. By adding or removing disks 165 thetotal weight can be'varied. The sheaves 162 and 163 are mounted on avertical frame 166. Attached to the upper end of one of the sidechannels 159 is a cable 170. The cable 176 passes over sheave 171 andserves to operate the indicator 23 of the gauge 29. The indicator 23 maybe weighted as at 172 so that it responds to movement of the swingingframe 22 in either direction. A hydraulic cylinder 175 is pivoted on themain frame of the machine at 176. Piston 177 of the 1 hydraulic cylinder175 is jointed at 178 and connected with the swinging frame '22 at thecenter of the lower channel 152. In actual operation, a weight 25 of 312pounds has been found to provide sufiicient tension in a web with abreaking strength of approximately 3000 pounds. The advantages inoperation, in economy of board, and in upkeep of the machine, of atension of approximately 10% of the breaking strength of the web over atension which, as indicated by the breakage of the Web in the machinesof the prior art, often exceeded the breaking strength, are clear.

Referring now'to Figures 2 and 3 for a detailed description of theintermediate pull roll 32 shown diagrams matically in Figure l. The rollis mounted on a driven shaft 75. The roll 32 is, however, free to rotateon shaft 75, being mounted'on ball bearings 76. The shaft is journaledin bearings 92 supported by stanchions 93. Keyed to the shaft 75 is aspider 77 on each of the four arms 78 of which is a yoke 79. Secured tothe end 80 iii of the roll 32 are pairs of cars 81. Loosely mountedwithin holes in the ears 81 are spring bolts 82 threaded at both endsand held in place against longitudinal move ment by jam nuts 83. Springs84, taking into spring cups 85 and 86, are carried by each of springbolts 82. When the roll drive is assembled, the yokes 79 of the arms 78of the spider 77 fit over the spring bolts 82 between springs 84 andbetween spring cups 85. The pull roll 32 is covered with rubber orsimilar material 90 to provide a better gripping surface than thatafforded by a polished metal roll. In the embodiment shown, one of thearms 78 is provided with a pointer 38'while a graduated plate 89 isfastened to the side 80 of the roll adjacent the pointer, by which ashift inthe relative positions of the spider and the roll from a centralneutral position is indicated. It will, of course, be necessary to use astroboscope to observe such a shift while the pull roll is in operation.

In practice, the registry of the cylinders of printers 12, 13, 14, and15 is regulated by electric eyes which control small differential gearsystems between the main shaft section 51 and the driven cylinders 11.These controls operate in increments of one-sixteenth of an inch so thatthey are unable to cope with any substantial slippage or pulsation ofthe web with respect to the cylinders. The operation of these electroniccontrols does not form a part of this invention and they are, therefore,not illustrated.

In operation, assume that a roll of paper board 2 is in place, that thepaper board has been threaded through the apparatus to form a web 4 andthat the motor 59 is running at a constant speed. Pull roll 3, drivenroll.

6, and feed roll 8 are so synchronized as to maintain the loop 7substantially constant though it can be seen that a certain amount ofleeway is permissible as long as the loop 7 does not become tooexaggerated or, conversely, disappear. e speed of feed roll 8 .isregulated by means of its variable speed transmission 62 to govern thespeed at which the paper board is fed to the printing section 100. Theprinting cylinders 11 are driven. If the feed roll 8 is set too slow,tension will be set up in the web between the feed roll and the printingsection, whereby the cylinders 11 will tend to slip ahead of the web andthe web may be broken. On the other hand, if the feed roll 8 is set torun faster than driven cylinders 11 the web will blister and produce, atleast at the first printers, a tendency for theweb to slip ahead of thedriven cylinders 11. in either event, the resulting printing is liableto be both smeared and out of registry. The actual printing operationdoes not form a part of this invention and will not be described.

After the web leaves the last printer 15 it passes over the top of theupper roll 26 and around the bottom of the lower roll 21 of the tensiondevice 17. From the lower roll 21 the web passes over an idler 30 andinto the nip of the pull roll 32. Assuming, for the moment, that thepull roll 32 represents the final pulling force on the web, it can beseen from'the construction of the tensioning device that as the tensionin the web between the final printer 15 and the pull roll 32 decreases,the weight 25 will rock the swinging frame 22 about its pivot 23, movingthe upper roll 20 away from the printing section and moving the lowerroll 21 toward that section. The rocking of the swinging frame 22 will,of course, within limits, maintain the tension of the Web substantiallyconstant, by taking up the slack in the web. Conversely, as the tensionin the web between the last printer 15 and the pull roll 32 increases,the tendency of the web to straighten will rock the swinging frame 22.against the weight 25 to move the upper roll 20 toward the printingsection 109 and the lower roll 21 away from that section. Again, withinlimits, the rocking of the swinging frame will maintain the tensionconstant. In the'first case the indicator 28 will be moved up withrespect to the gauge 29; in the second case the indicator 5 28 will bemoved downwith respect to the gauge 22. When the indicator 28 ismaintained substantially the center of the gauge 29 a constant tensionon the, web 4 is necessarily being maintained. If the pull roll 32 wereexerting the final pulling force on the web, it would be only necessaryto provide means for varying the speed of rotation of the pull roll 32with respect to the feed roll 8 and driven cylinders 11 to maintain thedesired tension in the web. However, in an pparatus of the characterhere involved, the blanker section 40 exerts a strong, and to someextent, independent, influence on the entire system. The relationsbetween the pull roll 32 and the blanker section 40 are fairly stable sothat once the proper relative speeds between pull roll 32 and theblanker section 40 are established the tension of the web between thefeed roll 8 and pull roll 32 may generally be adjusted by varying thespeed of the section 52 of the main line shaft, by which both pull roll32 and blanker section 46 are driven without having to change the speedrelation between pull roll 32 and blanker section 40. As has beenindicated, however, this is not universally true. A change in thecharacter of the board may produce a change in the tension balancebetween pull roll 32 and blanker section 40, since the characteristicsof the board with respect to the rubber-covered pull roll 32 may bequite diiierent from those with respect to the cutter, creaser, die andwaste cut-ofi rolls of the blanker section 40. in order to make the pullroll 32 adjustable with respect to the blanker section 40 the variable.

speed transmission 68 is provided between shaft section 52 and the pullr011 32. It has been found, however, that if it is attempted tosynchronize pull roll 32 with the blanker pull roll 41 there is atendency for the web to blister beyond the blanker pull roll 41,particularly during the part of the rotary cutter cycle during which theknives are not in contact with the web, to produce uneven blanking.Therefore, a variable speed transmission 61 is interposed between shaftsection 52 and blanker pull roll 41. The blanker pull roll is given anundertravel with respect to the remaining blanking rolls so that the webbetween the blanker pull roll and the remainder of the blanker rolls isunder tension from that source. To prevent breakage of the web from thetension between the blanker pull roll 41 and the remainder of theblanker section, blanker pull roll 41 is chromeplated and so constructedas to allow the web to slip thereover. For example, in a press in whichthe web speed is approximately nine hundred feet per minute theunder-travel of the blanker pull roll 41 with respect to the web and tothe remaining blanker rolls, hence; the

slippage of the web over the blanker pull roll, may amount to five feetper minute.

The nature of rotary blankers is such as to give rise to pulsation inthe web since the knives engage the web intermittently. Even when theblanker pull roll 41 has an under-travel with respect to the remainingblanker rolls, some of the pulsing of the web may be transmitted pastthe blanker pull roll 41 toward the printing section 199. it can also beseen that 'f the speed of the pull roll 32 is slow with respect toblanker section 4%, the tension is liable to be built up in the webbetween the blanker section 4%) and the pull roll 32, or that converselyif the pull roll 32 is set faster than the blanker rolls, the webbetween the pull roll 32 and blanker pull 1'011'41 will blister.

The construction of pull roll 32 is such as to damp the pulsation of theweb, to compensate for small variations in tension, and to permitobservation of tension changes between the blanker section 40 and thepress section 189. if the tension on the blanker section side of thepull roll 32 exceeds that on the printing section side the pointer 88 ofthe spider 77 of pull roll 32 will shift to the right in Figure 3. Ifthe tension on the printing section side exceeds that on the-blankersection side the pointer will indicate a shift to the left. Since eension qnt e pr ssefiqn sidecf h nu l. 91 32 is determined by the amountof weight 25 biasing the swinging frame 22, that weight will alsodetermine the tension in the web between the pull roll 32 and theblanker pull roll 41 when the pointer 88 of the pull roll 32 ismaintained in its central, neutral position. However, within reasonablelimits of tension between blanker pull roll 41 and pull roll 32 thetension between the blanker pull roll 41and the remaining blanker rollsis determined largely by the amount of over-travel of the latter rollswith respect to the blanker pull roll 41. With the construction of pullroll 32 described, variations in ten-. sion of the web between pull roll32 and blanker pull roll 41 which are within the capacity of the springs84, will not seriously disturb the blanking processes.

The spring suspension allows the pull roll 32 to damp the pulsation ofthe web without, however, simply blocking the pulsation completely. Ifthe pull roll 32 were rigidly mounted and the nip rolls 33 and 31 weresufliciently tight to block the pulse in the web from the blankersection 4.4] the resulting oscillation in the web between the blankersection and the pull roll 32 would tend to throw the blanker rolls outof registry with the web, and to break the web. The tensioning device 17serves as a further damper, in which role it is aided by the hydrauliccylinder'175 which simply serves to damp the oscillation of swingingframe 22.

The diiferential 56 between sections 51 and 52 of the main line shaft isespecially advantageous. When the system is running at a constant speed,the various sections may be properly synchronized for a web of givensurface characteristics. There is, however, still liable to be somevariation in the surface characteristics of the paper board runningthrough the system at any given time. These variations may be sufiicientto disturb the tension balance of the system. At the same time they maybe only temporary, as when the surface condition extends through only afew hundred yards of board or as when, during a change from one type ofboard to another, the unbalance obtains only until the new web occupiesthe whole machine. The differential 56 allows temporary correction to bemade quickly. By running the air motor 50 in one direction the section52 of the main line shaft may be slowed down with respect to the section51, to decrease the tension between the pull roll 32 and the printersection 190. 0n the other hand, if the air motor 57 is run in theopposite direction the section 52 is speeded up with respect to thesection 51 to increase the tension between pull roll 32 and printingsection 109. In either event when the air motor 57 is stopped theoriginal speed of rotation of the section 52 is restored. Thisarrangement is of particular utility when the machine is being speededup, as in starting, or slowed down, because the co-efficient of rollingfriction of the web and rolls varies with the speed at which the web istravelling. Thus if the various sections of the machine are set for asubstantially proper balance at a known working speed, the initialimbalance between the press section and the pull roll 32 may beover-come while the web is being brought up to speed, by thediiierential 56. When the desired operating speed has been reached anyminor, persistent imbalance between the pull roll 32 and the printingsection 1% may be corrected by adjusting the variable speed transmission55.

Another advantage of the differential 56 is that it responds quickly tointroduce a relatively great difl erence in speed between the sections.In order to provide the nicety of adjustment necessary in apparatus ofthis character the variable speed transmission 55 must necessarilyrespond slowly to adjustment. Thus if a major adjustment in the speedsbetween the sections 51 and 52 becomes necessary while the machine isrunning the balance may be maintained by means of the difier ential 56while the permanent adjustment is being made by means of the variablespeed transmission 55.

kept centered within narrow limits.

Numerous variations in the various elements of this invention within thescope of the appended claims will be apparent to those skilled in theart in the light of the foregoing disclosures. For example, the swingingframe 22 of the tensioning device 17 may be replaced by acounter-balanced idle roll journaled in sliding hearings to movevertically, with a pair of rolls on either side thereof and removedvertically beyond the limit of vertical travel of the counter-balancedidle roll.

In either embodiment of tension device switch means may be usedresponding to movement of the device to operate either the differentialgears or the variable speed transmission or both automatically tocorrect for the change in tension in the web. The blanket pull roll neednot be chrome-plated but may be otherwise made highlypolished enough toallow a smooth slippage without undue wear.

Thus it can be seen that means are provided for maintaining a propertension balance in a web of box board being printed and blankedthroughout a machine of the character described and for damping unwantedpulsation in the web, to allow proper registry of the printing pressesand of the blankers.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

I l. A continuous, rotar paper-board box printing press and blankerhaving an unwind roll and, in order from said unwind roll, a feed roll,printing rolls, a pull roll, and a blanking section containing powerdriven blanking rolls, said blanking section impart ng a pulsatingtravel to a web of paperboard being processed; and means for maintaininga substantially uniform tension in the web, substantially blocking thepulsations from the blanking section and permitting the maintenance ofregistry of the printing rolls and blanking section, said meanscomprising an idle roll about which the web passes, said idle roll beingmounted for translational movement in response to changes in ten sion inthe web and being biased against the tension in said Web, said idle rollbeing located between the last of said printing rolls and said pullroll, power means connected to rotate said pull roll, a resilientcoupling between said power means and said pull roll, and a blankingsection pull roll located between the said pull roll and the drivenrolls of the blanking section and having an undertravel with respect tothe driven rolls of the blanking section and to the web. a

2. The apparatus of claim 1, wherein the tension means includes upperand lower idle rolls mounted for rotation within a swinging frame andtraversed by the web, said springs of each pair being positioned on andengaged with opposite sides of an arm of said spider.

4. A continuous, rotary, paperboard box printing press and blankerhaving an unwind roll and, in order from said unwind roll, a feed. roll,printing rolls, a pull roll,

and a blanking section containing power driven blanking rolls, saidblanking section imparting a pulsating travel to a web of paperboardbeing processed; and means for maintaining a substantially uniformtension in the web, substantially blocking the pulsations from theblanking section and permitting the maintenance of registry of theprinting rolls and blanking section, said means comprising a tensiondevice loaded to maintain a substantially constant tension on said web,responding to variations i n tension of the web by movement from anormal position and located between the last of said printing rolls andsaid pull roll, power means connected to rotate said pull roll, and aresilient coupling between said power a 7 and blanket having an unwindroll and,. in order from said unwind roll, printing rolls and a blankingsection.

containing power driven blanking rolls, said blanking section impartinga pulsating travel to a web of paperboard being processed; and means formaintaining a substantially uniform tension in web, substantiallyblocking the pulsations from the blanking section and permitting themaintenance of registry of the printing rolls and blanking section, saidmeans comprising an idle roll around which the web passes, said idleroll being mounted for translational movement in response to changes intension in the web and being biased against the tension in said web,said idle roll being located between the last of the printing rolls andthe blanking section, and a blanking section pull roll, located betweenthe driven blanking rolls and the said idle roll, and having an under-.

travel with respect to the driven rolls of the blanking section and tothe web. V 7

6. A continuous, rotary, paperboard box printing press and blankerhaving an unwind roll and, in order from said unwind roll, printingrolls and a blanking section containing power driven blanking rolls,said blanking section imparting a pulsating travel to a web ofpaperboard being processed; an idle roll around which the web passes,said idle roll being mounted for translational movement in response tochanges in tension in the web and being biased against the tension insaid web, said idle roll being located between the last of the printingrolls and the blanking section, whereby the length of the web betweenthe last of the printing rolls and the blanking section is permitted tovary, and means located between the tension means and the drivenblanking rolls for damping the pulsations imparted to the web from saidblanking section.

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